KDE can be configured to support the PAM ("Pluggable Authentication
Modules") system for password checking by the display manager tdm and
by the screen saver tdescreensaver (for unlocking the display).
PAM is a flexible application-transparent configurable user-authentication
system found on FreeBSD, Solaris, and Linux (and maybe other unixes).
Information about PAM may be found on its homepage
http://www.kernel.org/pub/linux/libs/pam/
(Despite the location, this information is NOT Linux-specific.)
Known Solaris Issues:
--------------------
For compiling PAM support on Solaris, PAM_MESSAGE_NONCONST must
be defined. This should now be handled automatically by the
configure script.
Using PAM
---------
By default, PAM is automatically used, if it is found. Use
./configure --without-pam to disable it.
If PAM is found, KDE usually uses the PAM service "kde". You may
override it for all KDE programs by using --with-pam=<service> and/or
individually by using --with-<prog>-pam=<service>, where <prog> is
one of tdm, kcp and kss (for tdm, kcheckpass and tdescreensaver).
"make install" will attempt to create suitable service definitions; either
by putting files into /etc/pam.d/ or by adding text to /etc/pam.conf. The
services are just copies of the "login" service.
You may want to edit these definitions to meet your needs.
There are also two example service definitions in this directory -
kde.pamd and tdescreensaver.pamd - but don't just copy them!
If the services are misconfigured, you will NOT be able to login via TDM
and/or unlock a locked screen!
If there is ever any doubt about which PAM service a program was
compiled with, it can be determined by examining the PAM-generated
entries in the system log associated with tdm logins or tdescreensaver
authentication failures.
PAM configuration files have four types of entries for each service:
type used by tdm used by tdescreensaver
---- ----------- --------------------
auth x x
account x
password x
session x
There may be more than one entry of each type. Check existing PAM
configuration files and PAM documentation on your system for guidance as
to what entries to make. If you call a PAM service that is not
configured, the default action of PAM is likely to be denial of service.
Note: tdm implements PAM "session" support, which is not implemented in
certain PAM-aware xdm's that it may be replacing (e.g., the Red Hat
Linux 5.x xdm did not implement it). This may be configured to carry out
actions when a user opens or closes an tdm session, if a suitable PAM
module is available (e.g., mount and unmount user-specific filesystems).
Note 2: Screensavers typically only authenticate a user to allow her to
continue working. They may also renew tokens etc., where supported.
See the Linux PAM Administrators guide, which is part of the PAM
distribution, for more details.